Patients requiring therapeutic gas, for example, oxygen, may typically be administered that therapeutic gas via equipment such as a face mask or nasal cannula. That equipment is often connected to a gas source via flexible plastics tubing, and administration may occur in a domestic or clinical environment.
It has been established that the risk of fire when using such delivery apparatus with, for example, oxygen, oxygen enriched air, or any medical gas capable of supporting combustion, can be significant since the exposure of the apparatus to an ignition event can result in ignition. A flame which starts as an external fire supported by combustible gases leaking from delivery apparatus may then move to the interior of the flexible plastics tubing from delivery equipment and migrate rapidly upstream towards the gas source.
The fire hazard resulting from the use of such gas delivery apparatus is exacerbated in a domestic environment because the use of the oxygen is not supervised by health care workers. The presence of mandatory smoke detectors, fire alarms and other such safety equipment cannot mitigate the risks due to the rapidity of spread of a fire in, for example, an oxygen rich environment, once triggered. The risk of catastrophic fires, especially due to careless use of such apparatus is higher in the case of patients who smoke since there is a temptation for a patient to discard the oxygen delivery mask or cannula, and leave it in the vicinity, still delivering therapeutic gas, whilst a cigarette is smoked. Most oxygen delivery apparatus is set to deliver oxygen continuously at a rate determined by the needs of the patient, and removal of the delivery interface from the patient airway does not cause the delivery of oxygen to cease. In such circumstances an oxygen-enriched atmosphere can build up around the patient thereby preparing ambient surroundings for a catastrophic conflagration upon ignition.
There is therefore a need for apparatus and/or procedures to prevent or avoid fires spreading if an ignition event occurs in the proximity of the patient using combustible gas delivery equipment in a clinical or domestic environment.